1. Field of the Invention
This invention relates to a multi-purpose folding tool, commonly referred to as a compound or combination tool, since it includes a plurality of independently used tools, or as a survival tool, since it has rapidly become the tool of choice of outdoorsmen. A typical compound tool may incorporate pliers, flat-head and Phillips-head screwdrivers, knife blades, an awl, a pick, a fish cleaning serrated blade, a ruler, a wire insulation trimmer, and a bottle/can opener. Each of these independently used tools are typically housed in a single tool capable of folding into an easily carried, compact unit. Compound tools of this type are especially useful to those who need to maximize the utility of what they carry while minimizing the size and weight thereof, e.g. back-packers, bikers, campers, electricians, fishermen, hikers, and hunters.
2. Description of Related Art
Combination tools, i.e., those in which several different types of tools, e.g., a knife blade, an awl, or an assortment of screwdrivers and wrenches, are individually rotatable into and out of a housing for storage and use, respectively, have been the subject of U.S. patents for some time; see, for example, Barnard & Brace, U.S. Pat. No. 97,154, issued Nov. 23, 1869, and Pierce, U.S. Pat. No. 234,378, issued Nov. 8, 1880. Combination tools which include a pair of scissors or pliers, in which the crossed jaws fold into or adjacent to their handles, were developed around the turn of the twentieth century; see, respectively, Klever, Kaiserliches Patentamt, Patentschrift No. 30,788, issued Mar. 12, 1885, and Klever, U.S. Pat. No. 858,003, issued Jun. 25, 1907. The latter allows other tools, e.g., a knife blade, to be joined therewith, although the other tools are stored separately from the folded tool by inserting their base into a notch formed by the closed handles. Pliers having handles pivotally connected to the tangs of the pliers jaws, such that the handles fold adjacent the pliers jaws, are also known (e.g., Garrison, U.S. Pat. No. 1,461,270).
Combination tools including folding pliers in combination with other, supplemental tools, usually stored within the handles, the so called "survival tools", did not achieve widespread popularity until relatively recently with the patenting of such tools by Leatherman, U.S. Pat. Nos. 4,238,862, 4,744,272, and 4,888,869, and as evidenced in European Patent Application No. 513,937. Others followed quickly, e.g., Collins et al., U.S. Pat. Nos. Des. 368,634, and 5,062,173, Sessions et al., U.S. Pat. Nos. 5,142,721 and 5,212,844, and Frazer, U.S. Pat. Nos. Des. 368,634, and 5,267,366. All of these prior art tools are generally satisfactory for their intended purposes, but they do have drawbacks associated therewith.
In all of the folding tools cited above, from Klever to Frazer, the folding tools include straight handles. Thus, when the folding tool is closed, the jaws of the pliers are stored within the confines of the handles. Not only are the handles weakened by removing portions of the walls of the handles to receive the pliers, the space inside the handles is diminished, thereby decreasing the room available for the supplemental tools, which must perforce be made smaller and weaker.
Many folding tools position the plier head over some of the supplemental tools when completely closed. It is then necessary to go to the inconvenience of opening the plier portion of the tool when desiring only to access a supplemental tool. This then requires fully closing the plier portion of the tool again before you can actually use the supplemental tool.
The handles of Leatherman, Collins et al., Sessions et al., and Frazer are channel-shaped, open along their entire length, which may make them more susceptible to bending under heavy strains, particularly near the pivotal connection of the handles with the plier jaws' tangs, depending upon the thickness of the material.
The channel openings of Leatherman and Frazer (Design Pat. No. 368,634) open outwardly along the outer edge of the handles, i.e., outwardly in the plane of the handles. When squeezing the handles, the open channels and supplemental tools therein present rough surfaces and raw edges to the hands.
Prior art survival tools latch or lock the supplemental tools in their stored and extended positions by means of either (1) a leaf spring coacting with a flat on the periphery of the supplemental tools (e.g., Leatherman, Collins et al., Sessions et al., and Frazer), or by providing a projection at the end of the leaf spring to mate with a recess or notch in the periphery of the supplemental tools (Leatherman). The latter is the time-honored method used in related arts as well, such as, in jack-knives, vanity kits, or other specialized combination tools; see Halivarson, U.S. Pat. No. 1,556,788, Nielsen, U.S. Pat. No. 1,561,993, Bovee, U.S. Pat. No. 2,575,652, Bassett, U.S. Pat. No. 2,798,290, Zoeller, U.S. Pat. No. 2,851,704, and Felix-Dalichow, U.S. Pat. No. 4,442,600. In each of these, a projection on a separate lever or spring, or a flange on a resilient portion of the housing, fits into a notch on the supplemental tool to lock the tool in place. Alternatively, a projection on the tool mates with a seat or notch on the housing. Either way, a projection is designed to mate with a notch. Projections or flanges are difficult and costly to manufacture, and notching a tool to receive the projection usually results in lost material, and thereby lost strength, in the mounting end of the tool.
Though supplemental tools may lock in extended position to some degree, many tools have little or no provision for a completely positive lock. One reason is the resulting problem of providing an unlocking means that is safe, convenient and cost effective. With supplemental tools locking in a less than completely sure manner in the extended position, safe use can be questionable.
The jaws of pliers, wrenches, etc., have in the past occasionally been of a laminated construction, i.e., a plurality of sheets bound together by some means, often by rivets; see, e.g., Bernard, U.S. Pat. No. 526,480, McLeran, U.S. Pat. No. 831,676, Chen et al., U.S. Pat. No. 4,660,241, and Warheit, U.S. Pat. No. 4,662,252. In each of these, the laminations reinforce each other against forces acting transversely to the jaws, but they provide little to no resistance to shearing forces along the planar surfaces between the laminates.